Brake shoe grinder



NOV- 9, 1965 w. P. KUSHMUK ETAL 3,216,151

BRAKE SHOE GRINDER Filed July 3, 1965 4 Sheets-Sheet 1 INVENTORS Nov- 9 1955 w. P. KUsHMuK r-:TAL 3,216,151

BRAKE SHOE GRINDER 4 Sheets-Sheet 3 Filed July 3, 1965 INVENTORS ,5' P *f'fwmajc W. Q m w N C/ o Pal f? L?. Sana/e115' N0V 9, 1955 w. P. KUSHMUK ETAL 3,216,151

BRAKE SHOE GRINDER Filed July 5, 1963 4 Sheets-Sheet 4 75a IN VEN TORS @MM MZ? WM gf@ @g4/w United States Patent C) 3,216,151 BRAKE SHOE GRINDER Walter P. Kushmuk, Niles, and Ralph G. Sanders, Lake Villa, llil., assignors to Ammco Tools, Inc., Chicago, lll., a corporation of illinois Filed July 3, 1963, Ser. No. 292,692 8 Claims. (Cl. 51-96) This invention relates to grinders and has to do more particularly with a grinder for grinding arcuate surfaces such as the surfaces of automotive brake shoes.

Heretofore, typical grinders have been large, relatively complicated and expensive. They have included a grinder element, a base, a slide slidable on the base, toward and away from the grinder element, means for securingr the slide in a selected predetermined position on the base, a turntable pivotally supported on the base and a clamp slidably mounted on the turntable. This arrangement requires careful dimensioning of many parts.

The present invention provides a simple and elfective grinder which has all of the functions and advantages of the more complicated grinders now in use and at the same time has a structure which can be made simply and inexpensively and with a minimum of close tolerances.

An object of the present invention is to provide an effective, simple and inexpensive grinder for grinding arcuate surfaces.

Other objects and advantages will appear from the iollowing description taken with the appended drawings, wherein:

FIGURE 1 is a vertical, sectional view through a grinder constructed in accordance with the invention;

FIG. 2 is an end elevational view of the grinder of FIG. l;

FIG. 3 is a top plan view of the grinder of FIG. l;

FIG. 4 is a view of a detail;

FIG. 5 is a side elevational view partially in crosssection of the workpiece clamp in open position;

FIG. 6 is an enlarged view of a detail;

FIG. 7 is an enlarged face of the detent ring, and

FIG. 8 is a view of a section taken along line 8 8 of FIG. 6.

The grinder includes a base 10 on which is supported all of the other parts. The base 10 has a horizontal interior wall 11 having a depending portion 12 in which is fixed a bearing 13. A second bearing 14 is located in a seat in the wall 11 and a spindle 15 is journaled in the bearings 13 and 14. Carried on the spindle 15 is an abrasive wheel 16 of cylindrical form and having an abrasive outer surface.

The abrasive wheel 16 is rotated about its axis by an electric motor (not shown) which is located in a housing 17 and connected in driving relation to the spindle. A fan 18 is also carried on the spindle. A casing 19 having one side open is supported on the base 10 and surrounds the abrasive wheel.

A pivot support 2t) is provided which has a central bearing portion 21 in which is located a pivot pin 22 and side bearings 23. A pair of supporting shafts 24 and 25 are journaled in the bearings 23 and maintained against dislodgernent by pins 25a (two of which are shown) extending through the bearings said seated in grooves 26 in the shafts.

The shaft 25 extends through openings (not shown) in the base and is slidable therein. The shaft 24 extends through an opening 27 in the base 10 and is threaded through a sleeve 30. The sleeve 30 is rotatable in an opening 31 in the base and is held against longitudinal movement therein by a spring ring 32 against which the end of the sleeve 30 abuts and a spring ring 33 against which a shoulder 34 of the sleeve abuts.

The sleeve 30 may be turned in the bore 31 by a handle 35 secured on the sleeve as by a set screw 36. The sleeve 30 is held in any angular position of adjustment by detent means including a detent ring 37 provided with a peripherally arranged series of sockets 38 adapted to receive a ball 39 slidable in a socket 40 in the handle 35 and pressed outwardly by a spring 41. The detent ring is held against rotation by a tongue 42 which is located in a notch 43 in the base.

The handle 35 is provided on its periphery with a scale 35a cooperating with a mark 35b on the base which indicates the angular position of the sleeve 30 and thus the extent to which the shaft has been advanced in the sleeve.

It will be seen that rotation of the shaft 24 in one direction will cause the pivot support 20 and the members carried thereby (which members are hereinafter described) to be moved toward the grinder 16 and rotation in the opposite direction will cause the pivot support to be moved away from the grinder.

Carried on the front end (right-hand end as viewed in FIG. 1) of the shaft 24 is a handle 50 which is secured against rotation on the shaft by a pin 51 in a slot 52 but which permits longitudinal sliding movement of the handle on the shaft.

The handle 50 carries a locking pin 53 adapted to enter a notch 54 in the adjacent face of the pivot support to lock the handle 50 and the shaft 24 against rotation. The handle 50 is normally urged into position to engage the pin 53 in the slot 54 by a spring 55 located in a recess 56 in the handle and compressed between the bottom of the recess and a washer 57 secured to the end of the shaft.

It will now be seen that by pulling the handle 50 outwardly to disengage the pin 53 from the slot 54 the shaft 24 may be rotated to provide a coarse adjustment of the position of the shaft and the members carried thereby relatively to the grinder. On the other hand, when a fine adjustment is desired the sleeve 30 is turned by manipulation of the handle 35.

Pivotally supported on the pivot pin 22 and resting on the central bearing portion 21 of the pivot support 20 is a clamp pivot member 60 having a central bearing portion 61 which is received on the pivot pin 22. The clamp pivot member 60 has two parallel horizontal bearing portions 62. Extending rearwardly from the central bearing portion is an arm 63 having an upstanding end, the upper end of which is formed as a half-nut 65.

A lower jaw member 70 is provided which has two spaced parallel shafts 71 which extend through bores 72 in the bearing portions 62 and thus support the lower jaw for sliding movement on the clamp pivot member in a direction perpendicularly to the pivot axis.

The lower jaw 7() is provided with two spaced bosses or pods 75 against which a workpiece W is adapted to be clamped. Lateral bosses 75a are provided for engagement with the workpiece to position it.

An upper clamping jaw is provided which is pivoted on a pivot pin S1 secured in a clevis 82 upstanding from the floor of the lower jaw 70 for moving between open and closed position. A hairpin spring 83 coiled around the pin 81 with its ends bearing respectively on the upper and lower jaws urges the upper jaw to open position.

The upper jaw is formed with two sockets 84 in each of which a plunger 85 is slidable. Each plunger 85 is positioned to bear against one of the pads 75 when the upper jaw is in its closed position. Each plunger is secured against dropping out of its socket 84 by a screw 86 passing through the top of the socket. A coil spring 87 yieldably urges the plunger downwardly. Lateral bosses 84a are provided for engaging the workpiece.

An operating rod 90 is provided which is pivoted to the lower jaw 70 by a pin 91 extending through a socket 92 and is journaled in the lower jaw 70. The operating rod serves as means for rocking the clamp about its pivot when it is desired to grind the surface of a workpiece. It also serves as means for advancing the clamp toward the grinder element.

When a fast feed of the clamp is desired, as when the clamp is first advanced to bring the workpiece into engagement with the grinder element, the operating rod is raised out of engagement with the half-nut and into the position shown in FIG. 5. Thus the jaw may be slid on its support merely by pushing or pulling on the rod.

On the other hand, when a line or slow feed is desired, as when the workpiece is being ground, the operating rod is moved into engagement with the half-nut as seen in FIG. 1. When the operating rod is engaged with the half-nut, the clamp can be advanced or retracted by turning the operating rod about its own axis.

The movement of the operating rod about the pivot pin is utilized to open or close the upper jaw. To this end the socket 92 is provided with a clevis 95 housing a shaft 96 on which a roller 97 is pivoted. The roller 97 engages the under face of the upper jaw 80. When in the position shown in FIG. 5, the roller allows the jaw 80 to be moved to open position by the spring 83. On the other hand, when the roller 97 is moved into the position shown in FIG. 1, a camming action takes place and the upper jaw is moved to closed position. It will be seen that in closed position the roller 97 is slightly over center so that the upper jaw is locked in closed position.

A scale 100 is provided on the side of the base and an indicator 101 is carried by the shaft 24 and held in place by two spring rings 102. The indicator 101 in cooperation with the scale 100 indicates the position of the pivot center relatively to the surface of the grinder element. Thus the scale shows a diameter corresponding to the radius of the arc through which a workpiece will be swung when the operating rod is manipulated to swing the workpiece. For example, when the workpiece is to have a curvature corresponding to a diameter of 9", the shaft 24 is adjusted to a position wherein the indicator is opposite the numeral 9 on the scale.

In the use of the grinder, the operating rod 90 is moved to its upper position (FIG. to raise the upper jaw 80. The clamp is backed off from the grinder element by pulling out the hand wheel 50 and rotating the shaft 24. The workpiece is then inserted in the clamp with the ange resting on the pads 75 and the rim abutting the stops 75a. The operating rod is then lowered to engage in the half-nut 65. This action causes the roller 97 to cam the upper jaw 80 into closed position wherein it engages the plungers 85 with the workpiece flange and clamps it against the pads 75.

The shaft 24 is then rotated by the hand wheel until the indicator is opposite the mark on the scale which is nearest to the diameter to which the workpiece is to be ground.

Each revolution of the lhand wheel 50 advances the shaft 24 one-eighth of an inch. Thus, the clamp is set to the one-fourth inch nearest to the desired diameter. For a ne adjustment to the nearest one-thousandth of an inch the knob 35 is rotated appropriately until the desired scale indicia is opposite the indicator 35B.

The motor (not shown) is energized to rotate the grinder element 16. The operating rod is raised out of the half-nut 63 and the clamp is advanced until the workpiece is brought close to the surface of the grinder element. Thereafter, the operating rod is lowered into engagement with the half-nut and the clamp is advanced by rotating the operating rod about its own axis to feed the clamp toward the grinder element. Thus the workpiece is fed toward the grinder element.

We claim:

1. A grinder for grinding arcuate surfaces comprising a base, a cylindrical grinding element rotatably supported on said base, means on said base for rotating said grinding element, a pair of parallel shafts slidably supported by said base, a pivot support carried by said shafts for movement toward and away from said grinding element, a clamp pivot member, clamp pivot means pivotally supporting said clamp pivot member on said pivot support, for pivotal movement about a pivot axis parallel to the axis of said grinding element, and a workpiece clamp slidably supported on said clamp pivot member for sliding movement perpendicularly to said pivot axis.

2. A grinder as claimed in claim 1 wherein an internally threaded sleeve is supported in said base and held against rotation and one of said shafts is threaded through said sleeve whereby rotation of said one shaft moves said clamp toward or away from said grinding element.

3. A grinder according to claim 1 wherein one of said shafts is rotatable in said pivot support and base and disengageable means are provided for locking said one shaft against rotation.

4. A grinder according to claim 1 wherein one of said shafts is rotatable in said pivot support and base, a hand wheel is carried on said one shaft and disengageable means are provided on said hand wheel and said pivot support for locking said one shaft against rotation.

5. A grinder as claimed in claim 1 wherein there is provided an internally threaded sleeve rotatably supported in said base and held against longitudinal movement therein and one of said shafts is threaded through said sleeve.

6. A grinder as claimed in claim 1 wherein there is provided an internally threaded sleeve rotatably supported in said base and held against longitudinal movement therein, one of said shafts is threaded through said sleeve and disengageable means are provided for locking said sleeve against rotation in said base.

7. A grinder as claimed in claim 1 wherein said base is provided with an internally threaded opening threaded for receiving one of said shafts and disengageable means are provided for locking said one shaft against rotation.

8. A grinder according to claim 1 wherein an internally threaded sleeve is rotatably supported in said base and held against longitudinal movement in said base, one of said shafts is threaded through said sleeve,

disengageable means are provided for locking said sleeve against rotation and disengageable means are provided for holding said one shaft against rotation.

References Cited by the Examiner UNITED STATES PATENTS 3,060,644 10/62 Wisti 1 51--96 LESTER M. SWINGLE, Primary Examiner. 

1. A GRINDER FOR GRINDING ARCUATE SURFACES COMPRISING A BASE, A CYLINDRICAL GRINDING ELEMENT ROTATABLY SUPPORTED ON SAID BASE, MEANS ON SAID BASE FOR ROTATING SAID GRINDING ELEMENT, A PAIR OF PARALLEL SHAFTS SLIDABLY SUPPORTED BY SAID BASE, A PIVOT SUPPORT CARRIED BY SAID SHAFTS FOR MOVEMENT TOWARD AND AWAY FROM SAID GRINDING ELEMENT, A CLAMP PIVOT MEMBER, CLAMP PIVOT MEANS PIVOTALLY SUPPORTING SAID CLAMP PIVOT MEMBER ON SAID PIVOT SUPPORT, FOR PIVOTAL MOVEMENT ABOUT A PIVOT AXIS PARALLEL TO THE SLIDABLY SUPPORTED ON SAID CLAMP PIVOT MEMBER FOR SLIDING MOVEMENT PERPENDICULARLY TO SAID PIVOT AXIS. 